Consolidated Statements Of Changes In Equity (USD $) In Thousands	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Non-Controlling Interest [Member]
Balance at Dec. 31, 2012	$ 2,171,574	$ 458,646	$ 1,102,507	$ 477,210	$ (7,580)	$ 136,344	$ 4,447
Net income	60,808			61,017			(209)
Other comprehensive income	(6,581)					(6,581)
Distributions to non-controlling interest	(192)						(192)
Purchase of treasury stock	(29,993)				(29,993)
Issuance of stock under purchase and equity compensation plans	2,606		(1,146)		3,752
Net tax benefit related to equity compensation plans	181		181
Stock-based compensation	1,223		1,223
Issuance of nonvested stock awards	0		(1,320)		1,320
Cash dividends	(20,435)			(20,435)
Balance at Mar. 31, 2013	2,179,191	458,646	1,101,445	517,792	(32,501)	129,763	4,046
Balance at Dec. 31, 2013	2,214,397	481,224	1,279,948	449,836	(10,097)	9,731	3,755
Net income	64,121			64,313			(192)
Other comprehensive income	30,768					30,768
Distributions to non-controlling interest	(431)						(431)
Purchase of treasury stock	(20,900)				(20,900)
Issuance of stock under purchase and equity compensation plans	4,085		(2,897)		6,982
Net tax benefit related to equity compensation plans	800		800
Stock-based compensation	2,261		2,261
Issuance of nonvested stock awards	0		(6,822)		6,822
Cash dividends	(21,590)			(21,590)
Balance at Mar. 31, 2014	$ 2,273,511	$ 481,224	$ 1,273,290	$ 492,559	$ (17,193)	$ 40,499	$ 3,132